elections in the state of Texas are nonpartisan. Many local lawmakers have been impacted by the city's term limits. Several former city officials—Anthony Hall, Rodney Ellis, Sheila Jackson-Lee, Sylvia Garcia, Martha Wong, Chris Bell, Annise Parker, Shelley Sekula-Gibbs, Adrian Garcia, Ed Gonzalez, and Mike Sullivan—chose to run for other elected positions once their terms expired or shortly before they were due to expire. Former mayor Lee P. Brown denounced the term limits, saying they prevented incumbents from gaining enough experience in city government. A proposal to double the current two-year term of office has been debated—as of 2005, several candidates for the city council have brought up the issue of whether term limits should be amended or eliminated. Some elected officials from the Greater Houston area within the Texas Legislature—primarily Garnet Coleman and Sylvester Turner—have also spoken out against term limits. In 2010, a term limits review commission appointed by former mayor Bill White called for amending the city charter on extending term limits where elected officials could serve two four-year terms; the proposal failed 8.18.10 after the Houston City Council voted 7–7. The November 3, 2015 City of Houston municipal elections a referendum on the voter ballot have amended the term limit law where elected officials can serve two four-year terms - this measure does not abolish term limits nor have a reeligibility provision for past elected officeholders who served their full tenure under the 1991 term limit ordinance. Incumbents who have won re-election during the 2015 election under the three-term rule - those who served 2 are granted an additional 4 years while a freshman councilmember are granted their 2 additional terms - this means that some elected officials can hold up to 10 years in office (if a freshman councilmember who served during their 2014-16 term) or 8 years in office (for those elected in 2011 and re-elected to their final term). Houston has voted Democratic for the more than a decade and is liberal leaning. Currently, the majority of Houston elected officials are Democrats, and the city’s mayors have been Democrats for over 20 years. The city has become the most ethnically diverse city in the United States with immigrants from all over the world, adding a unique dimension to the city's politics. approximately 28% of the city's population is immigrants and there is no single identifiable ethnic group that holds a majority in the city.